Weird net::ERR_SPDY_PROTOCOL_ERROR errors when http2 emabled

[till.vollmer@…]

Chrome version 6.0.2924.87 (64-bit)
but also happens on Firefox but with a different error message

When I add http2 to my configuration some users get net::ERR_SPDY_PROTOCOL_ERROR
error.log is empty and access.log shows successfully requests

The weird thing is that it seems to be location dependent, meaning that I have locations where it never happens and in our office in Vienna always have it. Also the amount of files (images) seems to be relevant. up to 5 seem to work, but more fail. See screenshot of Chrome.

We use upstream to a unicorn Ruby in Rails server.

nginx config for this:

server {


	# SSL configuration
	#
    	listen 10.1.50.5:443 ssl http2 default_server;

        # ca-bundle merge and ciphers etc

        ssl_certificate /etc/nginx/cert/unkown.cacrt;
        ssl_certificate_key /etc/nginx/cert/unkown.key;
     
	root /home/unkown/server/mymind/current/public;

#app and cdn is redundant
    	server_name alpha.unkown.com ~^cdna\d+\.unkown\.com$;

        access_log /var/log/nginx/unkown-access.log;
        error_log /var/log/nginx/unkown-error.log;

        add_header X-Request-Origin xpreview;


# assets 

       location ~*  ^/(assets|images|javascripts|stylesheets)/.*\.(svg|ico|gif|jpe?g|png|js|css|html|ttf|ttc|otf|eot|woff|font.css)$ {
	     expires 365d;
     	 add_header Access-Control-Allow-Origin *;
         add_header etag "";
         add_header cache-control public;
       }  

# normal requests

	location / {

		try_files $uri @rails_normal;

	}


        location @rails_normal {
            proxy_pass      http://single_rest;
            proxy_redirect off;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header Host $http_host;
            proxy_set_header X_FORWARDED_PROTO "https";
            proxy_set_header   Host             $host;
            proxy_set_header   X-Real-IP        $remote_addr;
            proxy_connect_timeout      120;
            proxy_send_timeout         120;
            proxy_read_timeout         120;
            proxy_set_header CLIENT_IP $remote_addr;
            proxy_buffer_size   128k;
            proxy_buffers   4 256k;
            proxy_busy_buffers_size   256k;


        }
}

Here the log from chrome http2 network internals attached as file

[till.vollmer@…]

Files on request. Too big for attachments.

[WarriorXK@…]

Since chrome 58 i get the same error, IE, Safari and Firefox work fine for me. However other subdomains also using http2 don't have this issue.

[dave.g.bell@…]

I'm finding the same as WarriorXK, a previously working site stopped after a Chrome update. The error exists from all attempted connections in Chrome, different machines, networks and even a phone running Chrome give the same result.

The site runs fine in other browsers, and the server is also running a few other sites, using copied & pasted configs (tweaked only for domain, folder & "friendly URLs"), and these are running fine in the same Chrome browsers.

[Valentin V. Bartenev]

Please, provide a debug log from nginx as described here: ​http://nginx.org/en/docs/debugging_log.html and an HTTP/2 session log from chrome://net-internals tab.

[dave.g.bell@…]

After hours of searching Nginx files, testing, clearing every cache I could find, it turned out that one of our programmers had written header('/RedeemVoucher'); in the index.php, creating an invalid header because it should have been header('Location: /RedeemVoucher');

After putting the Location: bit in, it worked straight away.

[ericlaw1979@…]

Maybe there should be some sort of basic linter or other tool to flag these? Two other recent instances occurred due to an errant space or colon in the header name:

​https://groups.google.com/a/chromium.org/forum/#!topic/hstspreload/_uGEnwt_1_E
​https://www.michalspacek.com/chrome-err_spdy_protocol_error-and-an-invalid-http-header

[ayeshaggupta@…]

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[Maxim Dounin]

Feedback timeout. Likely an issue with headers returned by the upstream server. With changes in 41f4bd4c51f1 (nginx 1.21.1), nginx should be able to better detect and reject such broken headers from upstream servers.